ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[GuateGojira]

So, according with you guys, the authors are running in circles, as they already have a preconceive idea and the "analysis" is only corroborating it, instead of searching new conclusions.

Somehow, I feel compelled to backup they results, as if we actually face the facts, the traditional "subspecies" are based in practically nothing more than two or three specimens, only the Indochinese tigers were examined by more than 20 specimens. Besides, the clinal variation can be, at some point, less dramatic than what Mazák's size table can suggest.

For example, Amur-Bengal-Caspian tigers are/were of the same size, yes, I am pretty sure than the Caspian tiger was larger than the few available skulls suggest. I mean, check how few skull are of this population, but now check the photographs, there are specimens as large as the largest Bengal and Amur tigers. So, in the three more distant populations of mainland tigers (the "three kings"), they present the same size: c.200 cm in head-body, c.100 cm in shoulder height and a weight of 240-260 kg.

Now, let's go to the southeast of Asia, in Indochina and South China, those are classified as smaller animals, specially those from China. However, AGAIN, check the sample sizes. There only a dozen of skulls from China (males and females included) and another few from the entire Indochina area. However, if we see the documents of Kitchener (1999) and Kitchener & Yamaguchi (2010), the largest "Indochina" tiger skulls came from Malaysia, an area that is now popularly know for they "small" tigers. If we get the few data of China, those tigers seems small, but like I say, the sample is small, however, the largest specimen recorded is about the same size and weight than an average Amur tiger (190 cm in head-body and 190 kg), suggesting that probably, with more specimens, that clinal variation could be shown more clearly, with an "up" in the center of China, close to Manchuria and a "down" close to Indochina and again another "up" close to Thailand. Finally, in Indochina, some authors (I forgot they names, but @peter probably remember them) stated that the tigers in that area weighed up to 220 kg and there is the report of Baze of a giant tiger weighing 259 kg (570 lb) in this area, just like the heaviest Indian tigers. Probably it was a freak, but it shows that in the old days, the tigers in that area, with more prey, were as large as the "three kings".

Moving to Malaysia, those tigers were not the "dwarfs" that are popularized by Dr Kawanishi. He based his statements in two males that were "estimated" at 110 and 130 kg respectively, however when we see the table published in a conservation program document of Malaysia, we see that the size of those specimens are by no way correlated with those weights and in fact, the table itself stated that no weight was real, all were estimations as any scale was available at that time. The old records from the area present tigers as large as an average Indian specimen, and although Locke estimated them at no more than 160 kg empty, we know that body mass is affected more by prey availability than for "sub-speciation".

Finally, if we stay in the Indian subcontinent only, there is some variation if body mass, but the size remain the same. All tiger populations, from the entire Terai region, central India, and both west and east Ghats, tigers measure between 260-310 cm in total length, with no variations and no "ups" or "downs". In body mass, Terai tigers seems heavier, but in fact, Central Indian tigers are also very large with specimens weighing over 255 kg. The only Bengal tigers that weight less than that are those of Sundarbans and the Naga Hills, however those in the last area are based in very small samples and those from Sundarbans (modern ones at least) are based in frail specimens, some of them even unable to hunt. However, all these populations are "Bengal" tigers, and separate them in "subspecies" will be a silly mistake.

So, as we can see, there are very few variations in the mainland tigers and it seems that all populations were connected until the human intervention. Tigers can travel as far as 1,000 km, so male tigers from different areas could propagate they genes in distant areas beyond the "traditional" boundaries of the "subspecies". When only Mitochondrial DNA is used, we most take in count that female tigress are less prone to travel great distances, so the female genetic diversity is more focused in areas, and those can be interpreted as "subspecies-area cores", however, if Nuclear DNA (from males) is studied too, we could see more variations, as a young Bengal tiger could travel as far as the boundaries of the Indochina population and its sons even deeper. Only human presence stooped the tiger distribution, cutting the Amur-Caspian tiger population and later (as show by @GrizzlyClaws), the great China wall separated the China tigers from those of the Amur region, all this in historic times, at less than 200 years in some cases.

Mainland tigers have size peaks in the Amur, Caspian and Terai region, some medium points in the forest areas of South India, Indochina and Central China, and low values in lower Indochina, Malaysia and the China coastal areas. This, from my point of view, is a perfect clinal situation, and the differences in the skulls are just adaptations to the habitats, just like the modern humans skulls (again, check the skulls of the Mayan, Australian, European, Indian or the South of Africa, all natives, and all look different, but all are Homo sapiens).

On the islands, there is clear evidence that Javanese tigers were slightly larger than Sumatran ones, but this is based in the fact that the Javanese tigers had a best prey base than those of Sumatra. And about the Bali, we only have 9 skulls and a few skins, so we can't make clear conclusions and based in the last available pictures of Bali specimens, we can clearly say that the conclusions of Mazák that this tiger population was "small", are incorrect and should be discarded as "facts" and labeled just as "opinions" in his days. I suspect that, in the best days, Sumatran and Javanese tigers were of the same size, with a slight advantage for those of Java, meanwhile Bali tigers were probably smaller in comparison, but not the dwarfs that are popularly stated. I guess that Sundarbans tigers are/were the real "smaller-group" of tigers.

This is my appreciation, based in a quick analysis. Some points can be incorrect, but I bet that my appreciation is more conclusive than the old conceptions. However, like @tigerluver said, the concept of "subspecies" depends of the investigator, and this a real problem. Dr Kitchener proposed the "75% rule", but it seems that for other people, like Luo (in 2004 and 2010), a little genetic difference is enough to erect a new "subspecies", ignoring all the taxonomic rules and avoiding to provide AT LEAST one Holotype for her claims.

From this evidence, I think that the proposal of 2 subspecies, with 3 conservations units, for modern tigers, is accurate from a Biological point of view. Reply